No, because it's gmod.
1 - The AIM-9 Sidewinder is a heat-seeking, short-range, air-to-air missile carried mostly by fighter aircraft
2 - A dragon will not be able to act in time. Sidewinders travel at speeds faster than Mach 2. It would not even be able to hear it coming.
3 - It wouldn't get close enough, dear god you people. This isn't 1945 anymore, dogfights happen over miles of sky nowadays.
1 - Cold blooded, and confusing fire breath. The rocket would be better off non heat seeking and shot LOS.
2 - If the dragon chances directions all the time, the rocket would miss all the time. Really depends on your opinion on a dragon, since it is a myth.
3 - Once out of rockets it would have to get closer.
Also, how much rockets are we talking about. So far you guys are tring to say a single rocket will kill it.
Cold-blooded just means it needs to find an outside source to heat its blood. It's blood would still be warm, it just wouldn't be heat produced from its own body, right?
A little colder then normal though.